Senior Iranian officials indicated on Tuesday that progress was being achieved in expert-level talks between Tehran and six world powers over the implementation of a landmark nuclear deal.

But they added that the meeting, which began on Monday at the Vienna headquarters of the International Atomic Energy Agency (IAEA), the U.N. nuclear watchdog, would continue for a third day on Wednesday.

The goal is to work out details on implementing the November 24 interim accord under which Iran will curb its disputed nuclear program in return for some easing of sanctions that have battered its oil-dependent economy.

“The discussions are very smooth,” Hamid Baeedinejad, head of the Iranian delegation, said after the second day of talks.

“We have made our views known to each other with regard to the implementation aspects of each and every measure. That has been a very good exercise,” he told reporters. “We are trying to have unified understanding of each and every measure.”

Officials from Iran, the United States, China, Britain, France, Germany, Russia, the European Union and the IAEA attended the meeting in the Austrian capital.

Asked whether good progress was being made in the discussions, Iran’s ambassador to the IAEA, Reza Najafi, earlier told reporters: “Yes. We are going to continue tomorrow.”

Last month’s preliminary accord reached after marathon talks in Geneva is seen as a first step towards resolving a decade-old standoff over suspicions Iran might be covertly pursuing a nuclear weapons “breakout” capability, a perception that has raised the risk of a wider Middle East war.

Western diplomats said detailed matters not addressed at the November 20-24 talks in Geneva must be ironed out before the deal can be put into practice.

These include how and when the IAEA, which regularly visits Iranian nuclear sites to try to ensure there are no diversions of atomic material, will carry out its expanded role.

A start to sanctions relief would hinge on verification that Iran was fulfilling its side of the accord, they said.

Baeedinejad said the Iranian delegation had a “very good exchange” with senior IAEA officials during the meeting, but gave no further details.

The Geneva deal was designed to halt Iran’s nuclear advances for a period of six months to buy time for negotiations on a final settlement of the standoff. Diplomats say implementation may start in January after technical details have been settled.

Scope for easing the dispute peacefully opened after the June election of a comparative moderate, Hassan Rouhani, as Iranian president. He won in a landslide by pledging to ease Tehran’s international isolation and win relief from sanctions that have severely damaged the oil producer’s economy.